Troubleshooting your GPS connection

The preceding sections help to identify and solve most of the problems encountered when
connecting a GPS receiver to ArcPad. However, situations may arise in which you continue
to encounter problems connecting your GPS receiver despite verifying that both your GPS
and ArcPad have been configured correctly, and your GPS is connected to the device with
the correct cables. This section discusses some of these situations, as well as tools to
help troubleshoot your GPS connection.

“Error 55 opening COM1” message when activating the GPS

This error may occur when ArcPad attempts to open the serial port, such as COM1, when
the port has already been opened by another application. Any application that uses
the serial port could be responsible for this situation. On Windows Mobile devices,
however, the application is usually Microsoft ActiveSync, drivers for keyboards, or
programs used to configure GPS receivers. It is common on Windows Mobile devices for
applications to not release the serial port even though the application may no
longer be running.

The solution on Windows Mobile devices is to perform a soft reset, or reboot, of the
device. In practice, it is a worthwhile habit to always perform a soft reset of the
Windows Mobile device when switching from ActiveSync to using a GPS and vice versa.

This error message may also occur on PCs that have Microsoft ActiveSync running in
the background. The solution in this case is to open the Connection Settings dialog
box in ActiveSync and uncheck the Allow serial or infrared connection to this COM
port check box. This will disable ActiveSync from locking the serial port.

This situation may occur if you are using a portable keyboard that connects to the
serial port of your Windows Mobile device. The portable keyboard usually has an
associated program that runs in the background and regularly checks the serial port
for the keyboard.

The solution is to disable or exit the keyboard software before connecting your GPS
receiver. You may also need to do a soft reset of your Windows Mobile device.

Using HyperTerminal to test your GPS connection

HyperTerminal can be a very useful tool for testing your GPS connection communication
parameters and cables and verifying that the GPS receiver is outputting data using
the selected GPS protocol. HyperTerminal can also be a useful tool for determining
whether or not the cause of the connection problem is ArcPad. In most cases ArcPad
should be able to connect to your GPS receiver if HyperTerminal connects
successfully.

Opening HyperTerminal on PCs

To open HyperTerminal on PCs running Windows XP, click Start > Programs > Accessories
> Communications > HyperTerminal. This opens Hyperterminal with the New Connection
dialog box. Type GPS in the Name field of the New Connection dialog box and click
OK. Click OK in the Connect To dialog box.

In HyperTerminal, click the Properties button to open the properties dialog box.

In the Properties dialog box (which will be titled ‘GPS Properties’) select the COM
port you are using to connect to your GPS from the list in the Connect Using
drop-down list.

Click the Configure button to open the selected COM port’s properties. On the COM
Properties dialog box, select the communication parameters to match the settings on
your GPS receiver.

Click OK to save your settings and return to the main HyperTerminal window. Click the
Call (‘telephone’) button to connect to your GPS receiver.

The HyperTerminal window should show the data being received from your GPS
receiver—for example, ASCII NMEA sentences or illegible TSIP binary data. No data
displayed in the HyperTerminal window indicates a connection problem to your GPS
receiver